1. Field of the Invention
This invention relates to a thin film magnetic head and a method for manufacturing the same and, more particularly, to a thin film magnetic head and a method for manufacturing the same used for a stationary disk unit or a magnetic tape transport as an external memory for a computer.
2. Description of the Prior Art
A conventional method for manufacturing a thin film magnetic head of this type heretofore has the steps of preparing a substrate 21 made of a nonmagnetic material as shown in FIG. 3(a) and forming to reduce the thickness of the front end 22a of a lower core layer 22 made of a magnetic material much thinner than the rear end on the substrate 21 as shown in FIG. 3(b). The method further has the steps of forming a magnetic gap layer 23 made of a nonmagnetic material on the lower core layer 22 and perforating a through hole 23a for connecting the lower core layer 22 to an upper core layer 31 to be described later as shown in FIG. 3(c). The method subsequently has the steps of sequentially forming an interlayer insulating layer 26, a first layer first conductor coil layer 27, an interlayer insulating layer 28, a second layer second conductor coil layer 29 and an interlayer insulating layer 30 as shown in FIG. 3(d). The method further has the steps of forming the upper core layer 31 made of a magnetic material as shown in FIG. 3(e), and forming the upper core layer 31 in a predetermined shape as shown in FIG. 3(f). The method thereafter has the steps of coating it with a protecting layer (not shown), and polishing it to complete a conventional thin film magnetic head.
Since the magnetic gap layer 23 of the most important portion for the thin film magnetic head is effected by various actions in the steps of forming the interlayer insulating layers 26, 28 and 30 and the conductor coil layers 27 and 29 after forming the layer 23 in the conventional method for manufacturing the thin film magnetic head described above, there arise drawbacks that the magnetic gap layer 23 is damaged by a number of the steps to cause the characteristics to be deteriorated and the flatness and the dimensions to be aggravated.
Inasmuch as the end of the interlayer insulating layer 26 of the portion for restricting a gap depth is effected by various actions in the following steps in the same manner as the case of the magnetic gap layer 23 in the conventional method for manufacturing the thin film magnetic head, there also arise drawbacks that the dimensional accuracy is deteriorated to cause the gap depth to be difficult to be precisely formed.
Since the the position of a connecting point of the lower core layer 22 to the upper core layer 31 is low and the hole for connecting the upper core layer 31 to the lower core layer 22 becomes deep in the conventional method for manufacturing the thin film magnetic head, there also arise drawbacks that a crystal growth of the magnetic material for forming the upper core layer 31 is disordered on the oblique surface of the hole.